Industrial trucks



INDUSTRIAL TRUCKS Filed April 11, 1966 lump- I V m, m

a" v /r $22 F 2. 1039 ymztrg United States Patent ABSTRACT OF THE DISCLOSURE An industrial lift truck is provided with a chassis, a detachable mast releasably and pivotally mounted on the chassis at a point above the lower end of the mast, and two tilt-jacks, each jack being pivotally connected at one end to the chassis and at its other end to a common connecting member which is in turn releasably connected to the lower end of the mast. The arrangement is such that pivotal mounting of the mast on the chassis and the common connecting member provide means by which the mast is readily detachable from the chassis whilst maintaining the alignment of the tilt-jacks.

This invention relates to industrial trucks and more particularly to industrial trucks having masts.

In industrial lift trucks having a chassis which carries a mast it is usual to pivot the mast on the chassis at its lower end and to make it tilt by means of tilt jacks which extend from brackets on the chassis into engagement with the back of the mast at a suitable distance above the pivotal axis. Such masts are not readily detachable from the chassis of the truck because the construction puts the pivots and the connection of the tilt jacks to the mast into positions where they are shielded from ready access by surrounding parts of the truck. It is desirable that the bottom of the mast should not project substantially beyond the wheels and hence the pivotal connection is necessarily located between the front wheels of the truck, and the wheels prevent ready access thereto. It is an object of the present invention to provide a construction in which the mast can readily be removed and changed for another, for example, a two-section mast may be changed for a three-section mast which aifords a higher lift.

According to the present invention a lift-truck is provided with a chassis, a detachable mast pivotally mounted on the chassis by means of releasable trunnion bearings located at some distance above the bottom end of the mast, and a tilt-jack mechanism below the trunnion bearings which mechanism comprises a tilt-jack or jacks attached to the chassis of the truck and detachably connected to the mast.

It is preferred that the tilt-jack or jacks are connected to the mast by a member which is detachably secured to the mast and pivoted to the tilt-jack or jacks.

In this case the said member may comprise a cross member located at the bottom end of the mast and carrying pivotal connections for two tilt-jacks arranged sideby-side behind the mast. In one construction the mast has a permanent bottom cross member which rests on the cross member to which it is detachably secured, and the permanent bottom cross member supports a lift-jack on the mast.

alt is necessary to provide, with most masts, for the supply of hydraulic fluid to jack means on the mast, for example a lift jack for the load-lifting carriage. According to the present invention such a jack may be provided with a flexible hydraulic supply pipe and there may be a quick-release coupling by which the supply pipe can be connected to a supply on the chassis. In the case of I 3,394,828 Patented July 30, 1968 the coupling being on the chassis of the truck, the controls for the supply of hydraulic fluid to apparatus on the mast are all easily located on the chassis of the truck and when the supply pipe is connected up the apparatus on the mast will be immediately operable.

By way of example, a specific construction of truck in accordance with the invention will now be described with reference to and as shown in the accompanying drawings in which:

FIGURE 1 is an elevation of the truck; and

FIGURE 2 is a plan view of the truck shown in FIG- URE 1, part of the mast of the truck being shown in section.

With reference to the drawings, a truck 10 is provided comprising a chassis 11 having longitudinal lateral members 12 which, at the front end, carry downwardly extending brackets 13 supporting a drive axle 14 and ground wheels 15. The rear end of the chassis is also provided with further wheels 16 and means for steering them in known manner. The brackets 13 at the front end of the chassis 11 of the truck extend from an inverted channel section member 17 made from steel plate which member is bent longitudinally above the ground wheel 15 on each side of the truck so as to form front Wheel arches 18 over the ground wheels 15. Between the wheel arches 18 there is located a mast 19 having a first or fixed section comprising two upright members 20 of channel shape with the flanges of the channel members facing towards each other. The members 20 are united by cross members 21, 22 at top and bottom respectively and a second or movable section of the mast, which section comprises two uprights 20a, runs between them. Within the second section of the mast there is mounted a loadlifting carriage 23 to run up and down the uprights 20a and raise and lower loads. The bottom cross-member 22 of the mast supports a central upright lifting jack 41 for raising the movable section of the mast and the loadlifting carriage 2-3. A third section of mast, in known manner, may be provided if desired.

*On the outside of the outer channel members 20 of the mast 19 a short distance above the level of the top of the wheel arches 18 there are laterally projecting trunnions 24 and secured to the upper surface of each arch member 18 below the associated trunnion 24 is a bottom section 25 of a trunnion block 26. Recesses 27 in the bottom sections 25 of the trunnion blocks are provided for reception of the trunnions 24, the trunnion blocks taking the weight of the mast when the mast is located in position. Above each trunnion 24 is an upper or cap section 28 of the associated trunnion block 26 which upper section is pivoted at its rear end to the lower section of the block and is held down over the trunnion 24 by a bolt 29 directed upwardly from the lower section of the block and a nut 30 above it. The upper section 28 of the trunnion block is provided with a slot 31 to receive the bolt 29 and the bolt is hinged to the lower section of the block so that when the nut 30 is released, the bolt can be swung forward and then the upper section 28 of the trunnion block can be swung upwardly to release the trunnion 24 on that side of the mast.

Below the lower end of the mast 19 is an angle-section cross member 32 having an upwardly projecting upright flange 33 behind behind the mast and a forwardly projecting horizontal flange 34 below the cross-member 22 on the mast, the cross-member 22 being bolted to the horizontal flange 34 of the cross-member 32 by bolts 35 which are easily accessible from the front of the truck. Carried on the rear face of the upright flange 33 of the cross-member 32 are brackets 37 comprising pivotcarrying eyes which brackets are secured by pivot pins 38, to the rams 39 of two tilt jacks 40. These tilt jacks 40 are also pivoted on the chassis 11 of the truck at 44,

3 the jacks projecting forwardly therefrom towards the bottom of the mast 19. The lifting jack 41 on the mast 19 has a flexible hydraulic supply pipe 42 and the flexible pipe is led to a quick release self-sealing coupling 43 on the chassis 11 of the truck.

If it is desired to remove the mast 19 for any reason or to replace it by another mast, all that is necessary is to release the bottom cross-member 22 of the mast from the angle-shaped cross-member 32 to which it is bolted, to release the upper or cap sections 28 of the trunnion blocks 26 and to release the quick release self-sealing coupling 43 of the hydraulic supply to the lifting jack 41. The mast 19 together with the lifting carriage 23 mounted upon it can then be removed entirely by lifting it from the remainder of the truck with suitable tackle and it can, if desired, be replaced by another mast, which may be of different design provided it is such as to fit on to the angle-shaped bottom cross-member 32 to which the tilt jacks are connected and it carries tr-unnions 24 of a suitable size to engage the trunnion blocks 26 on the chassis.

One particular use for a truck of the type described above is in ports where the truck would sometimes be used on the quayside and at other times below decks on a ship. For this particular use and by means of this invention, the truck could be conveniently provided with a choice of two masts, one mast being, for example, a triple mast for use on the quayside and the other mast being a short one or two stage mast for use on the ships.

We claim:

1. An industrial lift truck having a chassis, a detachable mast, a releasable pivotal mounting connecting the mast to the chassis at a point above the lower end of the mast and a tilt-jack mechanism comprising two tilt-jacks, each jack being pivotally connected at one end to the chassis and pivotally connected at its other end to a separately constructed common connecting member which member is in turn releasably connected to the lower end of the mast and thereby below the said pivotal mounting of the mast on the chassis, the said releasable pivotal mounting of the mast on the chassis and the said common connecting member providing means by which the mast is readily detachable from the chassis while maintaining the alignment of the tilt-jacks.

2. A truck as claimed in claim 1 in which the mast comprises two spaced-apart uprights united by a cross-member at their lower ends and in which the said cross-member rests on the said common connecting member connnecting the said other ends of the tilt-jacks and is fixed thereto by detachable means which are located between the mast uprights and readily accessible from the front of the truck.

3. A truck as claimed in claim 1 in which the said pivotal mounting of the mast on the chassis comprises two horizontal shafts fixed to the mast and received within trunnion bearings fixed to the chassis of the truck, each trunnion bearing comprising a lower section fixed to the chassis and an upper or cap section capable of holding the associated shaft between the two sections of the bearing, the said upper or cap section being displaceable with respect to the said lower section to allow assembly of the shaft with and removal of the shaft from the bearing.

4. A truck as claimed in claim 3 in which the upper or cap section of each trunnion bearing is hinged to its associated lower section and in which means are provided for fixing the upper or cap section in a position which holds the associated shaft between the two sections of the bearing.

5. A truck as claimed in claim 1 in which the mast is provided with a load-lifting carriage and a jack for raising the carriage relatively to the mast, in which the jack is provided with a flexible hydraulic supply pipe and in which there is a quick release coupling by which the supply pipe is connected to a supply on the chassis.

References Cited UNITED STATES PATENTS 2,712,391 7/1955 Jones 214674 2,867,341 1/1959 Tieslau 214672 2,923,426 2/1960 Brandt 2l4672 X 3,081,891 3/1963 Prezybylski 214138 3,198,278 8/1965 Kaup 2l4--674 X 3,272,287 9/1966 Easton.

ROBERT G. SHERIDAN, Primary Examiner.

R. BALLANTYNE, Assistant Examiner. 

